Description
Based upon age determinations of subfossil wood samples found in the Khibiny Mountains of Russia's Kola Peninsula (67-68°N, 33-34°E) and the altitudes at which they were found, Hiller et al. determined that between AD 1000 and 1300 the upper tree-line within that region was located at least 100-140 m above its current elevation, which suggests, in their words, that mean summer temperatures during this "Medieval climatic optimum" were "at least 0.8°C higher than today."